Who is John Cabanis from Spoon River Anthology and what is their importance?

John Cabanis tells the reader he left the party of "law and order" to lead the liberal party not because of spite or forgetfulness or shiftlessness, but rather because he had a vision of democracy making every soul as "strong and fit to rule/ As Plato's lofty guardians." The reader learns in the Spooniad that, as the leader of the liberals, there was a bitter enmity between Cabanis and Thomas Rhodes, the leader of the Bank, and A.D. Blood the Mayor of Spoon River.